I'm very fascinated by this pattern. I did some research and didn't find many references to it. I only know now that it is a traditional pattern, I found a picture of a lovely quilt from 1880 showing this pattern in Jinny Beyer's wonderful book "Tessellation - Quilts entwerfen", she calls this pattern "Modified Spool" (and thankfully gives some instructions how to design the template), but mentions that it was also called "Applecore" or "Indian Hatchet". It also resembles the "Clamshell"- pattern, but it is always only a similarity, all these patterns mentioned above originally look more or less different. So, what becomes clear (and I searched the internet and all my Quilt-books, but still, I might be wrong here) is that this pattern was and is not widely used, and no wonder: it's for hand-sewing only, I find it impossible to use the machine here, even with larger pieces, all the curves don't fit when I try to assemble them with my machine - but then again, I'm not that good at machine-sewing in the first place. But all that makes it probably understandable why this pattern isn't that popular and even doesn't seem to have a proper name yet... I'll continue to call it "Spools", plus I will continue to use it for more projects, wallhangings, tablemats, quilts. As I said: I'm very fascinated by this pattern, I like that it's traditional and fine, that it is apparently rare, I like all these curves and small edges, I love the time and care it takes to put the pieces together and above all: I love when one curve meets the other and it all fits so nicely.
The detail above is from this tablemat:
